Aspirin Reduces Breast Cancer Occurence By Acting As An Aromatase Inhibitor?

In May of 2004 JAMA (The Journal of the American Medical Association) published an article titled ‘Association of Frequency and Duration of Aspirin Use and Hormone Receptor Status With Breast Cancer Risk’.

The citation for this article is Mary Beth Terry, PhD; Marilie D. Gammon, PhD; Fang Fang Zhang, MD, MPH; Heba Tawfik, MD, MPH; Susan L. Teitelbaum, PhD; Julie A. Britton, PhD; Kotha Subbaramaiah, PhD; Andrew J. Dannenberg, MD; Alfred I. Neugut, MD, PhD. Association of Frequency and Duration of Aspirin Use and Hormone Receptor Status With Breast Cancer Risk. JAMA. 2004;291:24 2433-2440.

A free copy of it is available at:

In summary, this article says that these researchers found evidence that aspirin use before and after menopause is associated with a significant reduction in breast cancer occurence risk for tumors that are estrogen or progesterin receptor positive, with recent use and frequency of use increasing the apparent risk reduction. They do not discuss doses, but other publications indicate that cancer risk reduction occurs with doses of 81-325mg per day. Estrogen and progesterone receptor negative tumors do not seem to be protected against by whatever mechanism is causing the protective effect.

Interestingly, the researchers also found a risk reduction in post menopausal females who took ibuprofen. But frequency didn’t seem to be a factor in the predictive effect. Perhaps there is another mechanism that is being observed here? Anyway, I remain uncertain relative to how to use the ibuprofen data.

As I’m sure you understand, there are many, many articles out there that discuss the association of aspirin and NSAID use and breast cancer risk reduction. Not all of them agree that there is a reduction benefit. Wanting to present you with an unbiased set of data to evaluate I suggest you take a look at this article to get a feel for the other point of view.

A. Heather Eliassen, ScD; Wendy Y. Chen, MD, MPH; Donna Spiegelman, ScD; Walter C. Willett, MD, DrPH; David J. Hunter, MBBS, ScD; Susan E. Hankinson, ScD. Use of Aspirin, Other Nonsteroidal Anti-inflammatory Drugs, and Acetaminophen and Risk of Breast Cancer Among Premenopausal Women in the Nurses’ Health Study II. Arch Intern Med. 2009;169(2):115-121.

You can find a copy of it at: It’s free.

Then again, there are a lot of articles that support the belief that aspirin and/or NSAIDs have a breast cancer chemoprevention effect. Like this one.

Bahi Takkouche, Carlos Regueira-Méndez and Mahyar Etminan. Breast Cancer and Use of Nonsteroidal Anti-inflammatory Drugs: A Meta-analysis.JNCI J Natl Cancer Inst (2008) 100 (20): 1439-1447. doi: 10.1093/jnci/djn324

You can find a copy of this article at: There is no cost for this document either.

We’re going to keep taking our 325mg of aspirin per day in my house.

As always, talk to your physician before starting or changing any medication regimen. Pharmacists Pharmacist. Doctors Doctor.